symbol constructors declared prefix missing a leading colon are accepted

data M = (++) Int
data N = (⌐) Int
data Ok = (:++) Int -- correctly accepted

I believe ghc should reject M and N. Instead M and N are accepted, but there seems to be no way to use that constructor (besides say a Data instance)

Trac metadata

Trac field	Value
Version	7.8.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Parser)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import parser labels

closed

Thanks for the report; it's a duplicate of #8556 (closed).

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedDuplicate

added Pnormal label